End cap for a hydraulic fitting

ABSTRACT

An end cap for an open end of a hydraulic fitting having a peripheral flange can be provided by a threaded ring and a threaded insert. The threaded insert can be rotatably engaged with the threaded ring to move axially back and forth. The threaded insert has a forward end face which can engage the open end of the hydraulic fitting to close the hydraulic fitting end or to couple with it. The threaded ring includes a locking member to embrace and engage the peripheral flange. The end cap can be used to prevent loss of oil from the hydraulic fitting during service of equipment on which the hydraulic fitting is utilized, and for other purposes.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

(Not applicable.)

The present invention relates to an end cap for a hydraulic fitting andto hydraulic, pneumatic or other fittings or equipment provided with theinventive end cap. More particularly, but not exclusively, the inventionrelates to an end cap suitable for closing or sealing an open end of ahydraulic fitting wherein the hydraulic fitting comprises a peripheralannular flange extending around the open end.

BACKGROUND OF THE INVENTION

There are a variety of circumstances in which it may be desirable toclose or seal the open end of a hydraulic, pneumatic or other fitting.For example, when hydraulic equipment such as a construction vehicle orthe like, is being serviced, oil-filled hydraulic lines, pipes andfittings are often disassembled during service and maintenanceprocedures. Much of the oil, or other working fluid, can be drained frommany of these components without undue difficulty but a residue willoften remain within the lines, pipes or fittings. This residual oil isprone to drip or drain from open fitting ends during service procedures,and may contaminate equipment surfaces, floors and other surfaces in thevicinity of the work area creating dirty, slippery and perhaps dangerousconditions. It is accordingly desirable to provide an end cap to closesuch open ends that can be easily manipulated in a service bay, aworkshop or in the field and can be assembled with an open ended fittingto close or seal it either by manual manipulation or by the use ofsimple tools. The presence of an annular flange around the end of somefittings may complicate the end closure problem.

To attempt to solve this problem it is known to provide a plastic cap tocover the fitting end. One example of such a plastic cap is a simple,lightweight, dish-shaped resilient cap which is a close fit over aflanged pipe end and has a modest retaining lip engagesble under theflange. Such plastic caps appear to be intended to keep out dirt and mayretain some oil within the pipe they may not be satisfactory for somepurposes because they are readily removed and cannot hold pressure.These shortcomings can be problematic in some cases, for example when itis desired to pressurize a flanged hydraulic fitting for test purposesor other reasons.

The patent literature contains proposals for end caps for hydraulicfittings. For example, U.S. Pat. No. 7,134,454 to Montminy discloses anend cap for blocking a pipe which employs a latch movable betweenlatched and unlatched positions to engage a rim around the end of thepipe. Also U.S. Pat. Nos. 4,205,707; 4,887,646; 4,982,763; 6,135,156;disclose various caps, plugs, closures or fittings for pipes, tubing andthe like.

Nevertheless, there is a need for an end cap that can be used to cap aflanged hydraulic fitting and which can be employed in a hydraulicequipment service facility and for other purposes.

The foregoing description of background art may include insights,discoveries, understandings or disclosures, or associations together ofdisclosures, that were not known to the relevant art prior to thepresent invention but which were provided by the invention. Some suchcontributions of the invention may have been specifically pointed outherein, whereas other such contributions of the invention will beapparent from their context. Merely because a document may have beencited here, no admission is made that the field of the document, whichmay be quite different from that of the invention, is analogous to thefield or fields of the present invention.

BRIEF SUMMARY OF THE INVENTION

The present invention provides, in one aspect, an end cap for an openend of a hydraulic fitting. Suitable hydraulic fittings can comprise aperipheral annular flange extending around the open end of the hydraulicfitting. The end cap can comprise a ring threaded about an axis and athreaded insert threadably engageable with the threaded ring. Thethreaded insert can thus move axially with respect to the threaded ringin response to rotation of the threaded insert with respect to thethreaded ring. The threaded insert can comprise a forward end face andcan be configured for the forward end face to be engageable with theopen end of the hydraulic fitting.

In addition, the end cap can include a locking member integral with thethreaded ring. The locking member can be configured to embrace theperipheral annular flange and can comprise a locking surface engageablewith a peripheral flange surface remote from the threaded ring. Thethreaded insert can be inserted into the threaded ring and can berotated to bring the threaded insert engagement surface into closingengagement with the hydraulic fitting. If desired, the threaded insertcan be rotatable to clamp the hydraulic fitting annular flange betweenthe locking surface and the engagement surface of the threaded insert.

In one embodiment of end cap according to the invention, the end face ofthe threaded insert can occlude and seal the open end of the hydraulicfitting.

In another embodiment of end cap according to the invention, useful as acoupling end cap, the threaded insert comprises a fluid passageextending through the threaded insert to communicate fluid from thehydraulic fitting through the end cap.

The locking member can define with the threaded ring a lateral openingto receive the hydraulic fitting annular flange in a directiontransverse to the axis. If desired, the threaded ring can comprise aside wall and the locking member can comprise a forward portion of theside wall.

In one embodiment of the invention, the side wall comprises a cutout,the cutout defines a side facing receiving opening and the side wall isundercut in the vicinity of the receiving opening to provide a U-shapedslot. With such a construction, the flanged open end of the hydraulicfitting can be laterally received in the receiving opening and can bemoved along the U-shaped slot.

In another embodiment of the invention, the locking member comprises alip engageable with the hydraulic fitting annular flange the lip havingan inner periphery with a part circular portion and two parallelstraight portions. The hydraulic fitting can be received between thestraight lip portions and the threaded insert can be rotated to clampthe hydraulic fitting annular flange between the peripheral lip and theengagement surface of the threaded insert. If desired, the lockingmember can comprise a continuous side wall joining the peripheral lip.

The hydraulic fitting can comprise a hydraulic pipe or hose end fittingand the invention includes a hydraulic system comprising the hydraulicfitting and an end cap according to the invention wherein the end capcaps the hydraulic fitting.

In another aspect, the invention provides a two-piece end cap for anopen flanged end of a hydraulic pipe or hose fitting, the end capcomprising a ring having a slot and an internal thread, wherein the ringcan slide over the flange in a direction radially of the hydraulicfitting with the slot in the ring receiving and accommodating theflanging of the flanged end and comprising a threaded plug wherein thethreaded plug can be screwed into the ring to seal the open flanged endof the hydraulic fitting.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

Some embodiments of the invention, and of making and using theinvention, as well as the best mode contemplated of carrying out theinvention, are described in detail herein and, by way of example, withreference to the accompanying drawings, in which like referencecharacters designate like elements throughout the several views, and inwhich:

FIG. 1 is a first side elevational view of one embodiment of end capaccording to the invention shown assembled with a hydraulic fitting,wherein the end plug closes an open end of the hydraulic fitting;

FIG. 2 is a second side elevational view of the end cap and hydraulicfitting assembly shown in FIG. 1 from a different direction;

FIG. 3 is a section on the line 3-3 of FIG. 2;

FIG. 4 is a rear perspective view of the end cap shown in FIG. 1, turnedthrough 90° as compared with the FIG. 1 view;

FIG. 5 is a front perspective view of the end cap shown in FIG. 4;

FIG. 6 is a front view of the end cap shown in FIG. 4;

FIG. 7 is a top view of the end cap shown in FIG. 6;

FIG. 8 is a lefthand side view of the end cap shown in FIG. 6;

FIG. 9 is a side elevational view of an embodiment of coupling end capaccording to the invention, assembled with the hydraulic fitting shownin FIGS. 1-3; and

FIG. 10 is a section on the line 10-10 of FIG. 9.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIGS. 1-8 of the drawings, the illustrated embodiment ofthe invention comprises an end cap 10 assembled with an annularhydraulic fitting 12 having an open end 14.

The illustrated embodiment of hydraulic fitting 12 comprises aperipheral annular flange 16 which extends continuously around open end14, projecting laterally from a tubular body 17 above a collar 19. Asshown, tubular body 17 of hydraulic fitting 12 has circular inner andouter cross-sectional shapes so that hydraulic fitting 12 is suitable toserve as a conduit for hydraulic fluid or to serve other purposes. Inthe illustrated embodiment, open end 14 of tubular body 17 has a plane,circular shape and the outer surfaces of tubular body 17 and annularflange 16 are smooth and free of threading, projections or otherstructure. Some other possible configurations of annular flange 16 aredescribed below and further possible embodiments will be, or become,apparent to a person of ordinary skill in the art in light of thisdescription.

Hydraulic fitting 12 can have any desired dimensions, with end cap 10being proportioned accordingly. For example, hydraulic fitting 12 canhave an internal diameter in the range of from about 1.5 mm to about 300mm (or from about 1/16 inch to about 12 inches). Some embodiments of theinvention are suitable for use with a hydraulic fitting 12 having aninternal diameter in the range of from about 12 mm to about 100 mm (orfrom about ½ inch to about 4 inches).

Hydraulic fitting 12 is exemplary of a wide range of hydraulic fittingsuseful for managing hydraulic fluids which can be capped by end cap 10to close open end 14, to connect open end 14 with another fluid conduitor fitting, to adapt the termination of open end 14, or to serve anotheruseful purpose. For example, hydraulic fitting 12 can be a flangedhydraulic fitting such as is supplied by Caterpillar and othermanufacturers in accordance with SAE Code 61 or SAE Code 62 or for otherpurposes. Some examples are Caterpillar #12 Code 61 and #20 Code 62 invarious sizes, for example with an internal tube diameter in the rangeof from about ½ in (about 12 mm) to about 3 in (about 75 mm).

Other hydraulic fittings, and other configurations of annular flange 16that can usefully be employed in practicing the present invention willbe or become apparent to a person of ordinary skill in the art.

In servicing certain types of hydraulic equipment, for example,construction machines such as a backhoe, a mechanical shovel, a frontloader or a bulldozer, hydraulic fittings such as hydraulic fitting 12are sometimes disconnected from other hydraulic components. Even if theequipment is drained beforehand, the resultant open end may dischargeresidual oil contaminating equipment or facility surfaces in thevicinity of the open end and possibly creating hazardous conditions.Simple plastic end caps may leak fluid, especially if hydraulic fitting12 is pressurized during maintenance for example for test purposes, orfor other reasons. It may also be desirable to adapt hydraulic fitting12 to have a different termination, for example a screw thread, or toprovide it with a connector to enable it to be connected it with otherequipment. Various embodiments of end cap according to the presentinvention, such as end cap 10, can solve or ameliorate one or more ofthese and other problems.

The embodiment of end cap 10 illustrated in FIGS. 1-8 comprises a ring18 threaded about an axis 20 and a threaded insert 22 which can bethreadably engaged with threaded ring 18. By virtue of the threading,threaded insert 22 can be advanced into threaded ring 18, or retractedtherefrom, by appropriate rotation of threaded insert 22 with respect tothreaded ring 18. Rearward end 23 of threaded insert 22 can beconfigured or structured to facilitate its being manually gripped, orengaged by a tool to rotate threaded insert 22 with respect to threadedring 18. For example, rearward end 23 can project rearwardly fromthreaded ring 18 when threaded insert 22 is fully advanced into threadedring 18 and can have an outer surface that is knurled, roughened orshaped with indents or projections to facilitate gripping or engagement.

In one embodiment of the invention, rearward end 23 is formed with flatsor depressions or has a hexagonal or other suitable cross-section to beengageable by wrench or other tool. Alternatively, rearward end 23 canbe axially recessed with a hexagonal or other shaped recess to receive asuitable tool.

In some embodiments of the invention, threaded insert 22 can be ofone-piece, integral or monolithic construction and can be fabricated bymachining, molding or casting from a suitable material. Threaded insert22 can be fabricated from any suitable material, for example, a suitablestructural synthetic polymer, such as a polycarbonate or nylon, a metalor metal alloy, aluminum alloy, steel or another ferrous alloy. In anembodiment of the invention suitable for heavy duty hydraulicapplications, for example for use with construction machinery, threadedinsert 22 can comprise a solid plug machined from steel or stainlesssteel.

In other embodiments of the invention, threaded insert 22 can have otherconstructions, as will be known or apparent to a person of ordinaryskill in the art. For example, threaded insert 22 can comprise two ormore components assembled together into an integral unit. One componentcould carry the threads and another component could comprise rearwardend 23 of threaded insert 22. Alternatively, or in addition, threadedinsert 22 can be hollow and optionally can be braced to give it greaterrigidity and strength, with one or more internal struts or crossmembers.

The embodiment of threaded insert 22 shown in the drawings comprises anend face 24 and is configured for end face 24 to be engageable with openend 14 of hydraulic fitting 12. For example, threaded insert 22 can beinserted into threaded ring 18 and rotated to bring end face 24 ofthreaded insert 22 into engagement with hydraulic fitting 12.

End face 24 is shown as being a plane surface which extends continuouslyacross insert 22 to fill the area of threaded ring 18 across axis 20 andto be capable of covering or closing, and potentially sealing, open end14 of hydraulic fitting 12 when brought into engagement therewith. Inother embodiments of the invention, end face 24 can have a non-planarstructure, being curved convexly or concavely, being conical or steppedor otherwise configured. If desired, end face 24 may have one or moreopenings, which opening or openings can be blind or can communicate withother structure or equipment, if desired. In further embodiments of theinvention, end face 24 can be recessed, or otherwise configured to beara seal, of a suitable material, for example a polymer such aspolytetrafluoroethylene, natural or synthetic rubber, copper, bronze orother suitable sealing material, the seal being designed to engage andseal against open end 14. Alternatively, end face 24 can besubstantially covered with a suitable sealing material secured to endface 24 by adhesive, stamping, welding, mechanical devices such as clipsor one or more bolts or screws, or by other suitable means.

In the illustrated embodiment of the invention, threaded ring 18 furthercomprises a locking member 26 which can be integral with threaded ring18 or is otherwise attached to threaded ring 18. Desirably, lockingmember 26 defines with threaded ring 18 a lateral opening to receiveannular flange 16 in a direction transverse to, or radially of, axis 20.For example, locking member 26 can be configured to embrace annularflange 16. Locking member 26 can have a locking surface 28 which isengageable with a peripheral surface 30 of annular flange 16 ofhydraulic fitting 12. Peripheral surface 30 desirably is disposed on theopposite side of annular flange 16 from open end 14. Also, lockingsurface 28 desirably is spaced apart from end face 24 of threaded insert22 so that annular flange 16 can be received between locking surface 28and end face 24 of threaded insert 22.

Accordingly, threaded insert 22 can be tightened, by rotating it, toclamp annular flange 16 of hydraulic fitting 12 between locking surface28 and end face 24 of threaded insert 22.

In one embodiment of the invention (not shown), locking member 26comprises one or more, desirably two or more, claw-like members that areperipherally spaced apart around threaded ring 18. Three or four, oranother suitable number, of claw-like members can be employed, ifdesired. Desirably, at least one of the spaces between adjacentclaw-like members is adequate to receive annular flange 16 between them,in a lateral direction, which is to say, transversely to axis 20. Forthis purpose, the spacing can be sufficient to receive at least thesmallest transverse dimension of annular flange 16. In the case of acircular annular flange 16, this dimension can be the diameter of theflange.

In the illustrated embodiment of the invention, locking member 26comprises a U-shaped lip 32 which is engageable with locking surface 30on annular flange 16. As illustrated, lip 32 has an inner peripherycomprising a part-circular portion 34, which optionally can beapproximately semicircular, and two parallel straight portions 36.Hydraulic fitting 12 and annular flange 16 can be received between thetwo straight portions 36 of lip 32.

As shown, threaded ring 18 comprises a continuous side wall 38 having aright cylindrical outer surface 40 and a right cylindrical inner surface42 which is threaded and which, in turn, defines a cylindrical volumethat can receive threaded insert 22. Outer surface 40 can have otherconfigurations, for example a hexagonal cross section, if desired, andcan be smooth, knurled, roughened or have another surfacecharacteristic, if desired. Lip 32 projects inwardly from the forwardportion of side wall 38, referring to the direction of engagement of endcap 10 with hydraulic fitting 12. In this embodiment of the invention,the forward portion of side wall 38, in the vicinity of slot 46,provides, or constitutes, locking member 26.

The forward end of threaded ring 18 has a cutout 43 in side wall 38which defines a side facing receiving opening 44. Side wall 38 isundercut in the vicinity of receiving opening 44 to provide a U-shapedslot 46 defined in part by lip 32. Receiving opening 44 and slot 46 canbe dimensioned and configured so that hydraulic fitting 12 can bereceived laterally into receiving opening 44 and can be movedtransversely of axis 20 to bring open end 14 of hydraulic fitting 12into axial alignment with end face 24 of threaded insert 22.

Desirably, annular flange 16 can be received into slot 46 and can bemoved along slot 46. For example, annular flange 16 can be a closesliding fit with slot 46 and can abut the curved portion of slot 46,with part-circular portion 34 of peripheral lip 32 engaging tubular body17 of hydraulic fitting 12, when properly aligned. This arrangement canprovide a stop locating hydraulic fitting 12 in alignment with threadedinsert 22.

Other arrangements and constructions of threaded ring 18 that will meetone or more of the objectives of the invention are possible. Forexample, threaded ring 18 can be formed with a second receiving opening(not shown) opposite to receiving opening 44, provided by a secondcutout and undercutting, to enable hydraulic fitting 12 optionally to bereceived into threaded ring 18 from the opposite direction. With thisarrangement, one or more detents and cooperative recesses, or othersuitable structures, can be provided to locate hydraulic fitting 12 inalignment with threaded insert 22.

When threaded insert 22 and hydraulic fitting 12 are suitably aligned,threaded insert 22 can be rotated, advancing threaded insert 22forwardly into threaded ring 18. The forward movement of threaded insert22 can bring end face 24 of threaded insert 22 into clamping engagementwith open end 14 of hydraulic fitting 12. The resultant forward thrustis borne by engagement of annular ring 16 with peripheral lip 32 ofthreaded ring 18.

In one embodiment of the invention, threaded ring 18 has a substantial,solid, plug-like construction. If desired, threaded ring 18 can be ofone-piece, integral or monolithic construction and can be fabricated bymachining, molding or casting from a suitable material. Like threadedinsert 22, threaded ring 18 can be fabricated from any suitablematerial, for example, a suitable structural synthetic polymer, such asa polycarbonate or nylon, a metal or metal alloy, aluminum alloy, steelor another ferrous alloy.

In other embodiments of the invention, threaded ring 18 can have otherconstructions, as will be known or apparent to a person of ordinaryskill in the art. For example, threaded ring 18 can comprise two or morecomponents assembled together into an integral unit. One component couldcarry the threads and another component could comprise locking member26.

In an embodiment of the invention suitable for heavy duty hydraulicapplications, for example for use with construction machinery, threadedring 18 can comprise a monolithic component machined from steel orstainless steel. For such applications, it can be desirable, for boththreaded ring 18 and threaded insert 22 to have sufficient strength forsubstantial torque to be applied so that end face 24 of threaded insert22 can exert an adequate axial closing force on open end of hydraulicfitting 12 to make an oil-tight, metal-to-metal seal.

Annular flange 16 of hydraulic fitting 12 can have a continuous ordiscontinuous construction. Continuous embodiments of annular flange 16can have various configurations, for example a circular outer periphery,as shown, a hexagonal, square or other polygonal outer peripheral shape,an oval, elliptical or other suitable outer peripheral shape. Thecross-sectional shape of annular flange 16 can be essentiallyrectangular, as shown or can be rounded, curved or triangular or anothersuitable shape. Two or more annular flanges 16 can be employed, and canfor example, be disposed closely together to function essentially as asingle flange.

Optionally, annular flange 16 can have a circular recess 48 extendingaround open end 14 to receive a sealing ring during normal use ofhydraulic fitting 12, as is known to a person of ordinary skill in theart.

Discontinuous embodiments of annular flange 16 can be employed, ifdesired. Such discontinuous embodiments can have one, two or moreperipheral gaps, can be essentially digitated, can comprise multiplelateral projections from tubular body 17, for example three or four ormore projections or short ribs or detent-like structures.

In another modified embodiment of the invention (not shown), threadedring 18 is externally threaded and threaded insert 22 comprises aninternally threaded sleeve to extend around threaded ring 18 and engagethe external thread. Threaded insert 22 can further comprise apiston-like member within the threaded sleeve which can extend throughthe externally threaded ring 18 to engage and seal open end 14 ofhydraulic fitting 12. For this purpose, the piston like member and theinner wall of threaded ring 18 can be smooth and close fitting, one tothe other, if desired.

Alternative means to threading can be employed for movably attachingring 18 to insert 22, if desired. For example an unthreaded version ofinsert 22 can be axially slidable in an unthreaded version of threadedring 18. In such an embodiment of the invention, one or more releasabledetents, clamps, or other suitable devices can be employed to hold theunthreaded insert engaged with open end 14 of hydraulic fitting 12.

One method of using end cap 10 comprises assembling threaded insert 22with threaded ring 18, if it is not already assembled, and rotatingthreaded insert 22 relatively to threaded ring 18 to screw threadedinsert partially into threaded ring 18, desirably stopping short of afully advanced position. If necessary, threaded insert 22 can be backedoff to a suitable partially advanced position. These steps can often beperformed manually, but a tool or tools can be employed, if desired.

End plug 10 can then be brought into engagement and assembled withhydraulic fitting 12. Gripping one component in one hand, and the othercomponent in the other hand, or in another suitable manner, end cap 10is moved towards hydraulic fitting 12 so as to cause locking member 26to embrace annular flange 16. Desirably, this movement can be effectedby aligning the components in the axial direction, with a lateral offsetone from the other, and then moving end cap 10 towards hydraulic fitting12 in a lateral direction to a point where the axes of the twocomponents are aligned and locking member 26 embraces annular flange 16.For example, referring to the illustrated embodiment, annular flange 16can be aligned with receiving opening 44 and then moved along U-shapedslot 46 until it is snugly located in the curved portion of U-shapedslot 46 with the axes of the two components aligned and with end face 24of threaded insert 22 opposite open end 14 of hydraulic fitting 12.

With end cap 10 appropriately assembled to hydraulic fitting 12,threaded insert 22 can be rotated into tight engagement with hydraulicfitting 12, by hand or by using a suitable tool to engage rearward end23 of threaded insert 22. Employing the embodiment of end cap 10illustrated in FIGS. 1-8 of the drawings, such tightening can bring endface 24 into sealing engagement with open end 14, the sealing thrustbeing taken by clamping engagement of lip 32 with annular flange 12.With annular flange 16 located in the curved portion of U-shaped slot46, the part-circular portion 34 and parts of the straight portions 36of lip 32 provide a secure seat for annular flange 16 permitting end cap10 to be securely clamped on to hydraulic fitting 12 with threadedinsert 22 closing, and optionally sealing open end 14 of hydraulicfitting 12.

In a modified embodiment of the invention (not illustrated) lip 32 has apart-circular recess which can closely accommodate annular flange 16 foraxial movement forwardly with respect to lip 32. The part-circularrecess defines ends of straight portions 36 of side wall 38 in thevicinity of cutout 43 which act as retainers preventing radial movementof annular flange 16 and hydraulic fitting 12 when annular flange 16 isseated in the recess. With this modification, a flanged hydraulicfitting 12 can slide into U-shaped slot of threaded ring 18 and can bemoved axially by rotating threaded insert 22 into threaded ring 18 andtightening end face 24 against flange 16 to drive flange 16 forwardlyalong the ring axis to seat in the recess in lip 32. In this position,flange 16 is securely locked against lateral movement out of end cap 10by the retainers constituted by the ends of straight portions 36 of sidewall 38 in the vicinity of cutout 43 and is unlikely to separate fromend cap 10 even when end face 24 is only loosely engaged with flange 16.

Useful embodiments of end cap 10 can be quickly and easily assembledwith hydraulic fitting 12 to provide a good leak-preventing seal withopen end 14 of hydraulic fitting 12. Furthermore, in some embodiments ofthe invention the assembled hydraulic fitting 12, end cap 10 can besubjected to significant hydraulic or pneumatic pressure from fluidsupplied within tubular body 17 for operational, service or testpurposes, without leakage.

The embodiment of coupling end cap 100 illustrated in FIGS. 9-10comprises a threaded insert 122 which differs from threaded insert 22 bycomprising an axial passage 102 and a rearward end 123 which is modifiedas compared with rearward end 23 of insert 22. Axial passage 102 permitsend cap 10 to function as a coupler and to be employed for couplingtubular hydraulic fitting 12 to another pipe, hose or other fitting orequipment for flow of hydraulic or other fluid to or from hydraulicfitting 12 and such other pipe, hose or other fitting. Rearward end 123of threaded insert 122 has a frusto-conical or tapered external endsurface 104 and a sidewall 106 bearing an external thread 108. Rearwardend 123 is adapted for connection with a flow meter, pressure gauge orother desired equipment or fitting. Rearward end 123 can have anydesired configuration, thread, diameter or other parameter according tothe equipment or fitting with which it is employed or to be employed.

Multiple threaded inserts 122 can be provided, if desired, incombination with one or more threaded rings 18, to provide a set ofcouplers capable of coupling hydraulic fitting 12 to a wide range ofequipment.

The forward end of threaded insert 122 is similar to that of threadedinsert 22 save for the presence of axial passage 102 which results inthreaded insert 122 having an end face 124 which is annular unlike theillustrated end face 24 of threaded insert 22 which is a continuoussurface intended for closing open end 14, although other configurationsof end face 24 are possible. Thus, threaded ring 18 also comprises alocking member 26 provided by side wall 44 configured with cutout 43 andU-shaped slot 46 to provide receiving opening 44. Similarly, couplingend cap 100 can be assembled with a hydraulic fitting 12 by axiallyaligning receiving opening 44 with annular flange 16 and sliding annularflange 16 along U-shaped slot 46 until annular flange 16 seats againstthe curved portion of U-shaped slot 46.

If desired, threaded insert 122 can first be assembled with otherequipment and then threaded ring 18 can be screwed on to threaded insert122 prior to attaching coupling end cap 100 to hydraulic fitting 12 toseal end face 124 against open end 14 of hydraulic fitting 12.

Useful embodiments of coupling end cap 100 can be quickly and easilyassembled with hydraulic fitting 12 and optionally with other equipment,to provide a good leak-preventing seal with open end 14 of hydraulicfitting 12. Furthermore, in some embodiments of the invention theassembled hydraulic fitting 12, end cap 100, and other equipment towhich rearward end 123 of threaded insert 122 is attached can besubjected to significant hydraulic or pneumatic pressure from fluidsupplied within tubular body 17 or axial passage 102, for operational,service or test purposes, without leakage.

The invention can provide a robust end cap 10 or coupling end cap 100which is securely held together and resistant to axial or lateral forcesfrom lateral or axial stresses or impacts, that may be imposed insubsequent maintenance or other operations. Embodiments of end caps suchas end cap 10 or coupling end cap 100 are useful in repair and serviceshops to assist in the maintenance of heavy industrial, construction ormilitary hydraulic machinery, and for other purposes, as will beapparent to a person of ordinary skill in the art.

Various possible embodiments and variations of end cap 10 or of couplingend cap 100 that can be employed in the practice of the invention willbe or become apparent to a person of ordinary skill in the art in lightof this disclosure.

The foregoing detailed description is to be read in light of and incombination with the preceding background and invention summarydescriptions wherein partial or complete information regarding the bestmode of practicing the invention, or regarding modifications,alternatives or useful embodiments of the invention may also be setforth or suggested, as will be apparent to one skilled in the art.Should there appear to be conflict between the meaning of a term as usedin the written description of the invention in this specification andthe usage in material incorporated by reference from another document,the meaning as used herein is intended to prevail.

While illustrative embodiments of the invention have been describedabove, it is, of course, understood that many and various modificationswill be apparent to those of ordinary skill in the relevant art, or maybecome apparent as the art develops, in the light of the foregoingdescription. Such modifications are contemplated as being within thespirit and scope of the invention or inventions disclosed in thisspecification.

1. An end cap for an open end of a hydraulic fitting, the hydraulicfitting comprising a peripheral annular flange extending around the openend, wherein the end cap comprises: (a) a ring threaded about an axis;(b) a threaded insert threadably engageable with the threaded ring tomove axially with respect to the threaded ring in response to rotationof the threaded insert with respect to the threaded ring, the threadedinsert comprising a forward end face and being configured for theforward end face to be engageable with the open end of the hydraulicfitting; (c) a locking member integral with the threaded ring, thelocking member being configured to embrace the peripheral annular flangeand having a locking surface engageable with a peripheral flange surfaceremote from the threaded ring; wherein the threaded insert can beinserted into the threaded ring and rotated to bring the threaded insertengagement surface into closing engagement with the hydraulic fitting.2. An end cap according to claim 1 wherein the threaded insert isrotatable to clamp the hydraulic fitting annular flange between thelocking surface and the engagement surface of the threaded insert.
 3. Anend cap according to claim 2 wherein the end face of the threaded insertcan occlude and seal the open end of the hydraulic fitting.
 4. An endcap according to claim 2 wherein the threaded insert comprises a fluidpassage extending through the threaded insert to communicate fluid fromthe hydraulic fitting through the end cap.
 5. An end cap according toclaim 1 wherein the locking member defines with the threaded ring alateral opening to receive the hydraulic fitting annular flange in adirection transverse to the axis.
 6. An end cap according to claim 1wherein the threaded ring comprises a side wall and the locking membercomprises a forward portion of the side wall.
 7. An end cap according toclaim 6 wherein the side wall comprises a cutout, the cutout defining aside facing receiving opening and the side wall is undercut in thevicinity of the receiving opening to provide a U-shaped slot and whereinthe flanged open end of the hydraulic fitting can be laterally receivedin the receiving opening and can be moved along the U-shaped slot.
 8. Anend cap according to claim 1 wherein the locking member comprises a lipengageable with the hydraulic fitting annular flange the lip having aninner periphery with a part circular portion and two parallel straightportions, the hydraulic fitting being receivable between the straightlip portions, the threaded insert being rotatable to clamp the hydraulicfitting annular flange between the peripheral lip and the engagementsurface of the threaded insert.
 9. An end cap according to claim 8wherein the locking member comprises a continuous side wall of thethreaded insert and the continuous side wall comprises the peripherallip.
 10. An end cap according to claim 8 wherein the lip has apart-circular recess to accommodate annular flange for axial movementforwardly with respect to the lip, the part-circular recess definingretainers in the straight lip portions, the retainers preventing radialmovement of a flange seated in the part-circular recess.
 11. An end capaccording to claim 1 wherein the threaded ring and the locking memberare both monolithic, one-piece members.
 12. An end cap according toclaim 1 wherein the hydraulic fitting comprises a hydraulic pipe or hoseend fitting.
 13. A hydraulic system comprising an end cap according toclaim 1 and a hydraulic fitting, the end cap capping the hydraulicfitting.
 14. A two-piece end cap for an open flanged end of a hydraulicpipe or hose fitting, the end cap comprising a ring having a slot and aninternal thread, wherein the ring can slide over the flange in adirection radially of the hydraulic fitting with the slot in the ringreceiving and accommodating the flanging of the flanged end andcomprising a threaded plug wherein the threaded plug can be screwed intothe ring to seal the open flanged end of the hydraulic fitting.